In this paper, we propose an efficient technique to statically manage integrity constraints in object-oriented database programming languages. We place ourselves in the context of an extended version of the O₂ database programming language, and we assume that updates are undertaken by means of methods. An important issue when dealing with constraints is that of efficiency. A naive management of such constraints can cause a severe floundering of the overall system. Our basic assumption is that the run-time checking of constraints is too costly to be undertaken systematically. Therefore, methods that are always safe with respect to integrity constraints should be proven so at compile time. The run-time checks should only concern the remaining methods. To that purpose, we propose a new approach, based on abstract interpretation, to prove the invariance of integrity constraints under complex methods. We then describe the current implementation of our prototype, reporting many experiments that have been performed with it on non trivial examples.